Mechanical characterization of thin injection-moulded polypropylene specimens under large in-plane shear deformations

Codolini, A.; Li, Q.M.; Wilkinson, Andrew

doi:10.1016/j.polymertesting.2018.06.010

Cited by 16 publications

(6 citation statements)

References 9 publications

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“…The sampling rate of the high-speed camera was set to be 5000, 50,000, 90,000, 120,000, and 135,000 frames per second, respectively. This method had been proved to be an efficient strain recording method for composites [22,[29][30][31][32][33]. The post-processing analysis of all the measurement results was conducted with the DIC professional software (VIC 2D 6, Correlated Solutions Inc., Irmo, SC, USA).…”

Section: Tensile Testing Methodsmentioning

confidence: 99%

The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

Cui

Wang

et al. 2019

Polymers

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Long glass fiber reinforced thermoplastic composites have been increasingly used in automotive parts due to their excellent mechanical properties and recyclability. However, the effects of strain rates on the mechanical properties and failure mechanisms of long glass fiber reinforced polypropylene composites (LGFRPPs) have not been studied systematically. In this study, the effects of strain rates (from 0.001 s−1 to 400 s−1) on the mechanical properties and failure mechanism of LGFRPPs were investigated. The results showed that ultimate strength and fracture strain of the LGFRPPs increased obviously, whereas the stiffness remained essentially unchanged with the strain rates from low to high. The micro-failure modes mainly consisted of fibers pulled out, fiber breakage, interfacial debonding, matrix cracking, and ductile to brittle (ductile pulling of fibrils/micro-fibrils) fracture behavior of the matrix. As the strain rates increased, the interfacial bonding properties of LGFRPPs increased, resulting in a gradual increase of fiber breakage at the fracture surface of the specimen and the gradual decrease of pull-out. In this process, more failure energy was absorbed, thus, the ultimate strength and fracture strain of LGFRPPs were improved.

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Section: Tensile Testing Methodsmentioning

confidence: 99%

The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

Cui

Wang

et al. 2019

Polymers

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“…Figure 10 is a schematic diagram comparing the shear properties of the geopolymers characterized in this study with typical properties found in literature for various materials 26–46 under V‐notch and Iosipescu testing methods.…”

Section: Resultsmentioning

confidence: 91%

V‐notched rail shear test applied to geopolymer composites

2022

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This work presents a systematic study of the shear properties of a potassiumbased geopolymer reinforced with distinct types of fibers. Chopped basalt reinforcements in lengths from 3 mm up to 50 mm and 13 μm in diameter were compared with thicker 20-mm length, basalt mini bars, sand-coated basalt mini rods, and steel fibers. The samples were tested under a V-notched rail shear tests (ASTM D7078), coupled with optical measurements, namely, digital image correlation, allowing a novel study of their crack patterns and failure modes under shear loading. In general, the use of chopped fibers resulted in shear strengths of up to 9 MPa and shear moduli of 4.3 GPa, with no significant variation with fiber length increments, neither in shear stress nor strain at peak load (0.1%). Mini bars and steel fiber reinforcements resulted in slightly lower shear stresses of 7.1 and 8.4 MPa, respectively. They exhibited greater strain values at peak loads, up to 2.1% which were attributed to fiber-matrix enhanced adhesions, thereby allowing gradual debonding and increased ductility. This effect was also recorded for mini rods, but at much lower strength levels, which did not contribute to their multiple cracking capacities. The alignment of the mini rods in 45 • directions resulted in a 50% increase in shear stress, showing the feasibility of tailoring the manufacturing process to attend to distinct demands.

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“…In-plane shear properties (τXY, Gxy) of PP and GF-PP composites were determined using the modified Wyoming Iosipescu test fixture, Figure 3, according to ASTM D5379-93. Codolini et al 28 investigated three in-plane shear testing methodologies on PP and noticed that ASTM D5379 was the best methodology for testing in-plane shear of PP. Simplified specimen preparation and approximately no stress concentration are the main advantages of using this kind of standard.…”

Section: Materials and Experimental Workmentioning

confidence: 99%

“…One of the best testing fixtures when dealing with polymers is the Wyoming Iosipescu test fixture. 28…”

Section: Introductionmentioning

confidence: 99%

“…One of the best testing fixtures when dealing with polymers is the Wyoming Iosipescu test fixture. 28 A group of studies have been made on investigating inplane shear of fabric thermosetting polymers made up by hand layup technique and adopted Iosipescu fixture in their studies. Abd-El-Baky and Attia 29 indicated that hybridizing jute fabric with glass and/or carbon fabrics in epoxy matrix composites improves the in-plane shear properties in both dry and wet conditions.…”

Section: Introductionmentioning

confidence: 99%

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In-plane shear and tensile behavior of two-pass injection-molded glass fiber reinforced polypropylene composites with different fiber lengths

Osama

Selmy

Abdelhaleem

et al. 2022

Journal of Composite Materials

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Glass fiber reinforced polypropylene (GF-PP) composites have proven a great potential in the designation and manufacturing of control arms, leaf springs, barriers, beams and bridge decks. Two-pass injection molding of GF-PP was investigated in this study. Polypropylene (PP) was injected with different weight fractions (w%) of chopped glass fibers (GFs) with different fiber feedstock lengths (FFSLs). The composites were then crushed and re-injected once again. Some specimens were burned out to check the actual weight fractions and fiber lengths after the injection processes. The fiber lengths dramatically decreased due to damages during two-pass injection processes and crushing. The manufactured specimens were tested in tension, and the results indicated that the tensile strength increased slightly at w = 10% of GF. Further increase of GF weight fraction leads to a drop in the tensile strength below neat PP. The results of SEM micrographs showed an increase in air voids concentrations at high GF percentages which clarifies the reason behind the drop in the tensile strength. Also, in-plane shear tests were carried out using the Iosipescu fixture where a slight increase in the in-plane shear strength was noticed by increasing fiber weight fractions. In-plane shear moduli of all specimens were measured experimentally by strain gauges and calculated theoretically. The shear modulus was enhanced by glass fiber addition and a further increase was noticed by increasing the fiber weight fractions.

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Mechanical characterization of thin injection-moulded polypropylene specimens under large in-plane shear deformations

Cited by 16 publications

References 9 publications

The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

V‐notched rail shear test applied to geopolymer composites

In-plane shear and tensile behavior of two-pass injection-molded glass fiber reinforced polypropylene composites with different fiber lengths

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